The subject matter disclosed herein relates generally to imaging systems, and more particularly, to a medical imaging system detector array and a method of manufacturing an imaging system detector array.
Detectors for diagnostic imaging systems, for example, a detector for a positron emission tomography (PET) imaging system, typically include a plurality of detector modules that are arranged in a ring. Each detector module includes an array of detector units. Each detector unit may include a plurality of detector scintillator elements that are configured to emit absorbed energy in the form of light. The scintillator elements transmit the light, via a light guide, to an array of light sensors that convert the light from the scintillators into an electric signal that is used to reconstruct an image of an object being scanned.
In at least one conventional detector array, the scintillator elements and the light guide are fabricated from different materials. Moreover, the scintillator elements and the light guide are fabricated as individual components that are coupled together using an adhesive. The light sensors are then coupled to the light guide using an adhesive to form a single detector unit.
The detector unit is typically designed to control the transport of the photons generated in a scintillator element of the scintillator array to each sensor in the sensor array. If the photon transport for every scintillator element in the detector unit is adjusted such that it produces a unique intensity pattern on the sensor array, the number of scintillator elements that a detector unit can process can be larger than the number of light sensors in the detector unit. To facilitate controlling the photon transport from the scintillator elements to the sensor array, the light guide may be constructed of several segments with a reflective optical barrier between the segments. However, because the scintillators and the light guide are fabricated using different materials, the refractive index of the scintillators may be different than the refractive index of the light guide. Moreover, the refractive index of the adhesive bonding the light guide to the scintillator elements and the light sensors may be different than the refractive indexes of the scintillator, the light sensor, or the light guide. As a result, these detector units may have a refractive index mismatch between the scintillators, the light guide, the light sensor, and/or the adhesive. The refractive index mismatch may result in a reduction in the intensity of the light signal transmitted from the scintillators to the light sensor. Moreover, because numerous individual scintillator elements are bonded to a single light guide, it is often difficult to properly align the scintillators with the light guide. As a result, specialized alignment devices are utilized to properly align and bond the scintillators to the light guide.